An Approach to Autonomizing Legacy Systems

Adding adaptation capabilities to existing distributed systems is a major concern. The question addressed here is how to retrofit existing systems with self-healing, adaptation and/or self management capabilities. The problem is obviously intensified for 'systems of systems' composed of components, whether new or legacy, that may have been developed by different vendors, mixing and matching COTS and 'open source' components. This system composition model is expected to be increasingly common in high performance computing. The usual approach is to train technicians to understand the complexities of these components and their connections, including performance tuning parameters, so that they can then manually monitor and reconfigure the system as needed. We envision instead attaching a 'standard' feedback loop infrastructure to existing distributed systems for the purposes of continual monitoring and dynamically adapting their activities and performance. (This approach can also be applied to 'new' systems, as an alternative to 'building in' adaptation facilities, but we do not address that here.) Our proposed infrastructure consists of multiple layers with the objectives of probing, measuring and reporting of activity and state within the execution of the legacy system among its components and connectors; gauging, analysis and interpretation of the reported events; and possible feedback to focus the probes and gauges to drill deeper, or when necessary - direct but automatic reconfiguration of the running system

A Uniform Programming Abstraction for Effecting Autonomic Adaptations onto Software Systems

Most general-purpose work towards autonomic or self-managing systems has emphasized the front end of the feedback control loop, with some also concerned with controlling the back end enactment of runtime adaptations -- but usually employing an effector technology peculiar to one type of target system. While completely generic "one size fits all" effector technologies seem implausible, we propose a general purpose programming model and interaction layer that abstracts away from the peculiarities of target specific effectors,enabling a uniform approach to controlling and coordinating the low-level execution of reconfigurations, repairs,micro-reboots, etc

A Uniform Programming Abstraction for Effecting Autonomic Adaptations onto Software Systems

Most general-purpose work towards autonomic or self-managing systems has emphasized the front end of the feedback control loop, with some also concerned with controlling the back end enactment of runtime adaptations but usually employing an effector technology peculiar to one type of target system. While completely generic 'one size fits all' effector technologies seem implausible, we propose a general-purpose programming model and interaction layer that abstracts away from the peculiarities of target-specific effectors, enabling a uniform approach to controlling and coordinating the low-level execution of reconfigurations, repairs, micro-reboots, etc

Using Process Technology to Control and Coordinate Software Adaptation

We have developed an infrastructure for end-to-end run-time monitoring, behavior/performance analysis, and dynamic adaptation of distributed software. This infrastructure is primarily targeted to pre-existing systems and thus operates outside the target application, without making assumptions about the target's implementation, internal communication/computation mechanisms, source code availability, etc. This paper assumes the existence of the monitoring and analysis components, presented elsewhere, and focuses on the mechanisms used to control and coordinate possibly complex repairs/reconfigurations to the target system. These mechanisms require lower level effectors somehow attached to the target system, so we briefly sketch one such facility (elaborated elsewhere). Our main contribution is the model, architecture, and implementation of Workflakes, the decentralized process engine we use to tailor, control, coordinate, etc. a cohort of such effectors. We have validated the Workflakes approach with case studies in several application domains. Due to space restrictions we concentrate primarily on one case study, briefly discuss a second, and only sketch others

A survey on online monitoring approaches of computer-based systems

This report surveys forms of online data collection that are in current use (as well as being the subject of research to adapt them to changing technology and demands), and can be used as inputs to assessment of dependability and resilience, although they are not primarily meant for this use

A Case Study In Software Adaptation

We attach a feedback-control-loop infrastructure to an existing target system, to continually monitor and dynamically adapt its activities and performance. (This approach could also be applied to 'new' systems, as an alternative to 'building in' adaptation facilities, but we do not address that here.) Our infrastructure consists of multiple layers with the objectives of 1. probing, measuring and reporting of activity and state during the execution of the target system among its components and connectors; 2. gauging, analysis and interpretation of the reported events; and 3. whenever necessary, feedback onto the probes and gauges, to focus them (e.g., drill deeper), or onto the running target system, to direct its automatic adjustment and reconfiguration. We report on our successful experience using this approach in dynamic adaptation of a large-scale commercial application that requires both coarse and fine grained modifications

The economics and business models of prescription in the Internet

L'économie de l'Internet a contribué à une ouverture du jeu concurrentiel en dissociant les fonctions physique et informationnelle des activités de distribution. Plus précisément, elle a ouvert la voie à de nouvelles structures de marché en mettant en avant une fonction de prescription clairement distincte des fonctions d'offre d'une part, des fonctions logistiques et de mise à disposition des biens d'autre part. Nous nous attachons ici à montrer que l'analyse des fonctions et modalités de prescription permet de mieux comprendre les modèles d'affaires et les structures concurrentielles à l'œuvre dans l'économie de l'Internet organisées autour de l'articulationde trois marchés : biens primaires, référencement, prescription. Cette modélisation de marchés à prescription contribue à enrichir la compréhension des chaînes de valeur et des relations d'affaires repérables dans l'Internet.prescription;internet

A Case Study In Software Adaptation

We attach a feedback-control-loop infrastructure to an existing target system, to continually monitor and dynamically adapt its activities and performance. (This approach could also be applied to 'new' systems, as an alternative to 'building in' adaptation facilities, but we do not address that here.) Our infrastructure consists of multiple layers with the objectives of 1. probing, measuring and reporting of activity and state during the execution of the target system among its components and connectors; 2. gauging, analysis and interpretation of the reported events; and 3. whenever necessary, feedback onto the probes and gauges, to focus them (e.g., drill deeper), or onto the running target system, to direct its automatic adjustment and reconfiguration. We report on our successful experience using this approach in dynamic adaptation of a large-scale commercial application that requires both coarse and fine grained modifications

Retrofitting Autonomic Capabilities onto Legacy Systems

Autonomic computing - self-configuring, self-healing, self-optimizing applications, systems and networks - is a promising solution to ever-increasing system complexity and the spiraling costs of human management as systems scale to global proportions. Most results to date, however, suggest ways to architect new software constructed from the ground up as autonomic systems, whereas in the real world organizations continue to use stovepipe legacy systems and/or build 'systems of systems' that draw from a gamut of disparate technologies from numerous vendors. Our goal is to retrofit autonomic computing onto such systems, externally, without any need to understand, modify or even recompile the target system's code. We present an autonomic infrastructure that operates similarly to active middleware, to explicitly add autonomic services to pre-existing systems via continual monitoring and a feedback loop that performs, as needed, reconfiguration and/or repair. Our lightweight design and separation of concerns enables easy adoption of individual components, independent of the rest of the full infrastructure, for use with a large variety of target systems. This work has been validated by several case studies spanning multiple application domains